Cancers and Autoimmune Diseases

  • Making a Case for Necropsy in the Alpaca: When You Hear Hoof Beats, Don’t Look for Zebras

    There is an old saying in medicine, “When you hear hoof beats, don’t look for zebras.” It loosely suggests that, when a doctor, or in this case a veterinarian, sees symptoms of a disease, the most common cause of the symptoms is usually the culprit. In the case of a common infection this adage is a simple reminder for doctors that a fever is more likely a cold or flu – and not infectious endocarditis. Which brings me to the purpose of my article which is to inform my fellow alpaca ranchers of a rare illness found in one of our alpacas. In other words, the rare hoof beat that was in fact, a “zebra.” More importantly, I hope to alert you in how not to miss that alpaca with the rare disease. The one that can add to the body of knowledge for all alpaca owners, enabling them to better understand disease in the alpaca.More »
  • Malignant Round Cell Neoplasia in Llamas and Alpacas

    Malignant round cell neoplasia was identified in 12 llamas and 12 alpacas aged 0–23 years. Mean age of affected alpacas (3.1 years) was significantly less than that of affected llamas (8.0 years). Tumor cell morphology varied from large and often pleomorphic (11 tumors) to small and often homogeneous (13 tumors). Neoplastic lesions were multicentric in 12 cases. Other sites were gastric (5 cases), intra-abdominal (perirenal; 4 cases), intrathoracic (2 cases), and cervical (1 case). Immunohistochemistry with antibodies to CD79α, BLA36, and CD3 identified B-cell lymphoma (12 cases) and T-cell lymphoma (6 cases). Six tumors did not express any lymphoid marker and were further immunostained for neuron-specific enolase (NSE), synaptophysin, S-100, glial fibrillary acidic protein (GFAP), and chromogranin A. All 6 of these tumors were negative for GFAP and chromogranin A but expressed 1 or more of the neural markers NSE, synaptophysin, and S-100 and were classified as primitive malignant round cell tumors (PMRCT). Tumor types could not be distinguished on the basis of animal age, gross pathologic appearance, tumor morphology, or tumor location. All animals with lymphoma and 5 with PMRCT died or were euthanatized. One alpaca with a focal cervical PMRCT lived for at least 20 months after diagnosis. Results of this study indicate that malignant round cell tumors in llamas and alpacas are a heterogeneous group that cannot be distinguished on the basis of signalment, postmortem findings, or routine light microscopic findings. Immunohistochemistry is a valuable diagnostic procedure when evaluating malignant round cell neoplasia in llamas and alpacas.More »